1. Field of the Invention
The present invention relates to a film feeding device for winding and rewinding a photographing film. More particularly, the invention relates to a film feeding device which can perform film feeding driving from a film cartridge toward a winding spool.
2. Description of the Related Art
In some photographing films, a leading portion of the film is completely accommodated within a cartridge. When the cartridge accommodating such a film is loaded into a camera or the like, a spool within the cartridge (hereinafter termed a xe2x80x9ccartridge spoolxe2x80x9d) is driven by a film feeding mechanism provided within the camera or the like, in order to perform feeding driving (thrust driving) of the film from within the cartridge.
Together with such thrust driving, a spool for winding up the film (hereinafter termed a xe2x80x9cwind-up spoolxe2x80x9d) is simultaneously driven within the camera, so that the film is subjected to winding driving. After loading the film cartridge, thrust driving and winding driving of the film are performed to allow a photographing operation.
After completing all photographing operations, winding driving of the film into the cartridge (rewinding driving) is performed by inversely rotating the cartridge spool.
Mechanisms for performing the above-described film driving are proposed, for example, in Japanese Patent Laid-Open Application (Kokai) Nos. 3-206435 (1991) and 4-225338 (1992).
(1) For example, in the film feeding mechanism disclosed in Japanese Patent Laid-Open Application (Kokai) No. 3-206435 (1991), when simultaneously performing thrust driving of a film by driving of a cartridge spool and winding driving of the film by driving a wind-up spool using a one-way clutch, any difference between the thrust-driving speed and the winding-driving speed is cancelled.
(2) In the film feeding mechanism disclosed in Japanese Patent Laid-Open Application (Kokai) No. 4-225338 (1992), speed-difference cancellation means is provided in the proximity of the cartridge spool, in order to minimize the load given to a moter by a slip torque of the speed-difference cancellation means.
(3) The assignee of the prensent application has proposed a film feeding mechanism similar to that described in item (1), in which by incorporating a spool gear integrated with a wind-up spool in a gear train as an idler gear in thrust driving or rewinding driving, the spool gear, serving as means for inputting a driving force to the wind-up spool, also operates as means for transmitting power to the cartridge spool.
However, in the film feeding mechanisms described in items (1) and (2), a gear train for transmitting a driving force to the wind-up spool and a gear train for transmitting a driving force to the cartridge spool during winding driving of the film are disposed as different gear trains. As a result, there arise problems, such as the requirement of additional space for arranging the gear trains at both sides of the spool gear, an increase in the number of gears, and a decrease in the driving-force transmission efficiency.
In the film feeding mechanism described in item (3), the spool gear integrated with the wind-up spool is incorporated within the gear train for performing thrust driving and rewinding driving as an idler for the gear train. Hence, during rewinding driving of the film after completing photographing operations for all frames of the film, the wind-up spool performs feeding driving of the film in the direction of the cartridge. Accordingly, if the amount of feeding of the wind-up spool is larger than the amount of winding of the cartridge spool, the film is loosely wound within a spool chamber where the wind-up spool is accommodated, thereby preventing a smooth rewinding operation.
It is an object of the present invention to solve the above-described problems.
It is another object of the present invention to provide a film feeding device having a small size in which switching of a feeding direction can be reliably performed.
According to one aspect of the present invention, a film feeding device includes a driving source, a spool gear, provided on a film wind-up spool, to which a driving force of the driving source is transmitted, a cartridge-spool driving gear for transmitting the driving force of the driving source to a cartridge spool within a film cartridge, a clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the spool gear to the cartridge-spool driving gear when meshed with the spool gear, and a moving mechanism for moving the clutch gear from the unmeshed position to the meshed position with respect to the spool gear by transmission driving by the driving source.
According to another aspect of the present invention, a film feeding device includes a driving source, a spool gear provided on a film wind-up spool, a first clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the driving source to the spool gear when meshed with the spool gear, a cartridge-spool driving gear for transmitting the driving force of the driving source to a cartridge spool within a film cartridge, a second clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the spool gear to the cartridge-spool driving gear when meshed with the spool gear, and a moving mechanism for moving the second clutch gear from the unmeshed position to the meshed position with respect to the spool gear, linked with a movement of the first clutch gear from the meshed position to the unmeshed position with respect to the spool gear.
According to still another aspect of the present invention, a film feeding device includes a driving source, a spool gear provided on a film wind-up spool, a first clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the driving source to the spool gear when meshed with the spool gear, a cartridge-spool driving gear for transmitting the driving force of the driving source to a cartridge spool within a film cartridge, a second clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the spool gear to the cartridge-spool driving gear when meshed with the spool gear, and a moving mechanism for moving the second clutch gear from the unmeshed position to the meshed position with respect to the spool gear by transmission driving by the driving source, and for moving the second clutch gear from the unmeshed position to the meshed position with respect to the spool gear, linked with a movement of the first clutch gear from the meshed position to the unmeshed position with respect to the spool gear.
According to yet another aspect of the present invention, an optical apparatus includes a film feeding device. The film feeding device includes a driving source, a spool gear, provided on a film wind-up spool, to which a driving force of the driving source is transmitted, a cartridge-spool driving gear for transmitting the driving force of the driving source to a cartridge spool within a film cartridge, a clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the spool gear to the cartridge-spool driving gear when meshed with the spool gear, and a moving mechanism for moving the clutch gear from the unmeshed position to the meshed position with respect to the spool gear by transmission driving by the driving source.
According to yet a further aspect of the present invention, an optical apparatus includes a film feeding device. The film feeding device includes a driving source, a spool gear provided on a film wind-up spool, a first clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the driving source to the spool gear when meshed with the spool gear, a cartridge-spool driving gear for transmitting the driving force of the driving source to a cartridge spool within a film cartridge, a second clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the spool gear to the cartridge-spool driving gear when meshed with the spool gear, and a moving mechanism for moving the second clutch gear from the unmeshed position to the meshed position with respect to the spool gear, linked with a movement of the first clutch gear from the meshed position to the unmeshed position with respect to the spool gear.
According to yet another aspect of the present invention, an optical apparatus includes a film feeding device. The film feeding device includes a driving source, a spool gear provided on a film wind-up spool, a first clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the driving source to the spool gear when meshed with the spool gear, a cartridge-spool driving gear for transmitting the driving force of the driving source to a cartridge spool within a film cartridge, a second clutch gear, movable between a meshed position and an unmeshed position with respect to the spool gear, for transmitting a driving force of the spool gear to the cartridge-spool driving gear when meshed with the spool gear, and a moving mechanism for moving the second clutch gear from the unmeshed position to the meshed position with respect to the spool gear by transmission driving by the driving source, and for moving the second clutch gear from the unmeshed position to the meshed position with respect to the spool gear, linked with a movement of the first clutch gear from the meshed position to the unmeshed position with respect to the spool gear.
The foregoing and other objects, advantages and features of the present invention will become more apparent from the following description of the preferred embodiment taken in conjuction with the accompanying drawings.